Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net loss	$ (8,525)	$ (14,009)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	240	303
Stock issued for supplemental stock issuance agreement	0	5,154
Warrant revaluation and other finance expense	1,663	3,050
Depreciation and amortization	140	222
Provision for doubtful accounts	0	5
Change in operating assets and liabilities:
Accounts receivable	1	(35)
Inventory	27	91
Prepaid expenses and other current assets	201	317
Other assets	0	72
Accounts payable	774	(2,055)
Accrued expenses and other long-term liabilities	1,069	931
Deferred revenue	172	1
Net cash used in operating activities	(4,238)	(5,953)
Cash flows from investing activities:
Purchase of property and equipment	(108)	(79)
Net cash used in investing activities	(108)	(79)
Cash flows from financing activities:
Proceeds from the issuance of common stock	152	0
Net cash provided by financing activities	152	0
Net decrease in cash and cash equivalents	(4,194)	(6,032)
Cash and cash equivalents, beginning of period	37,495	60,033
Cash and cash equivalents, end of period	$ 33,301	$ 54,001